Re: Liquid Emulsion Questions
From: Philip Ringler <omkali23@hotmail.com> Subject: Liquid Emulsion Questions Date: Fri, 22 Sep 2006 23:56:11 -0700 > I want to make high contrast, Liquid emulsion prints on plywood > Approximately 4'x4' I need to set up a system in a darkroom so I can > coat, expose and fix the piece of wood in a standardized way, > meaning I need to have a set-up so that it is consistent. [...] There are a few points that you need to establish separately. 1. High contrast. High contrast emulsion requires higher level of emulsion technology, and I doubt liquid emulsion can be made that high contrast. Changing developers (within conventional formulation) won't help you much as long as you seek pictorial quality (not lith quality). If the contrast is inadequate, I suggest that you make a duplicate negative with sufficient contrast. This should solve the problem most cleanly. However, before trying anything else, make sure your coating weight is appropriate. If not enough emulsion is coated, the contrast tend to be low. (But coating beyond a certain point won't help you.) Also, it's important that the substrate is very white. If the substrate is dark colored, you won't get contrast. 2. Hazardous fixer. A fixer solution that was used only once is not that hazardous, unless you use a lot of it. If you are concerned about environment, you should select a fixer that does not contain any borate or EDTA. I have published formulae for such fixers online in the past, but you can also buy such a fixer as well (google "Clearfix Fixer"). 3. If you are concerned about hazard, I would be more concerned about minimizing accidental exposure to the developer. Large prints, large liquid light projects, etc. tend to use a large amount of solution and perhaps in nonstandard way (spraying, brushing, pouring, etc.) and the potential risk of accidental exposure is greater. 4. I have printed on paper using homemade emulsions, although the size was 22x30 inch. I always did it by immersion, and I think immersion is the best if you can make a suitable container to work in. You want to make a tray with drain valve at the bottom, and use "single tray" technique with it. I use 3 feet tray and lift up to pour the solution back to a gallon jug, but this requires me to stand up on a stool when securely holding the tray to transfer the solution. A large deep tray with drain valve at a lower corner would be perfect. A cheap large tray substitute can be found at Home Depot (the stuff to put under a laundry washing machine). However, I find those products too small, too flimsy, too shallow, etc. and I actually use stuff I bought from B&H. (Though it costed more.) 5. You should be worried about even development of the material. If you find this to be a problem, I'd use slightly weaker print developer (Tektol Neutral 1+14, Dektol 1+5, Multigrade 1+14, etc.) and give sufficiently long developing time to complete development.
|